Coining presses

ABSTRACT

A coining press is disclosed having a pair of opposing dies, the lower die is substantially stationary during the coining operation and the upper die moves toward the lower to engage a blank disposed between them. A press slide is mounted to reciprocate in the direction of the lower die. A tooling slide carries the upper die and is slidably mounted in the press slide to move along a line toward and away from the lower die and is spring urged away from the lower die toward the press slide to normally engage a stationary stop. The total travel of the tooling slide makes up only a small part of the travel of the press slide in order that the upper die will have a normal rest position only just above the lower die, and free of a carrier member used to feed blanks between the dies.

- United States Patent Merriman et al.

COINING PRESSES Filed: on. 17, 1969 App]. No.: 867,229

Foreign Application Priority Data Oct. 19, 1968 Great Britain .49,709/68 US. Cl. ..72/446, 72/447, 72/462, 72/465 Int. Cl. ..B2lj 13/02 Field of Search ..72/413, 434, 446, 447, 354, 72/358, 352, 353, 462, 465

References Cited UNITED STATES PATENTS 11/1966 Kraft ..72/4 l/1971 Staecker ..72/4 8/1888 Knapp ..72/354 12/ 1 927 Talcott ..72/446 1/1938 Almdale ..72/446 2/ l 939 Hauschild ..72/434 [151 3,683,667 [451 Aug. 15, 1972 2,245,642 6/ 1 941 Bell ..72/447 2,417,569 3/1947 Rice ..72/353 3,477,270 1 1/1969 Finsterwalder ..72/26 3,526,122 9/ 1970 Hemingway ..72/462 FOREIGN PATENTS OR APPLICATIONS 939,551 10/1963 GreatBritain ..l00/DIG.18 657,256 9/1951 Primary Examiner-Charles W. Lanham Assistant Examiner-Gene P. Crosby Attorney-Scrivener, Parker, Scrivener and Clarke [57] ABSTRACT A coining press is disclosed having a pair of opposing dies, the lower die is substantially stationary during the coining operation and the upper die moves toward the lower to engage a blank disposed between them. A press slide is mounted to reciprocate in the direction of the lower die. A tooling slide carries the upper die and is slidably mounted in the press slide to move along a line toward and away from the lower die and is spring urged away from the lower die toward the press slide to normally engage a stationary stop. The total travel of the tooling slide makes up only a small part of the travel of the press slide in order that the upper die will have a normal rest position only just above the lower die, and free of a carrier member used to feed blanks between the dies.

6 Claims, 2 Drawing Figures Great Britain ..72/415 7 PATENTEDAUB 15 I972 SHEET 1 [IF 2 PATENTEDAUG 1 5 m2 3 6 83,667 SHEET 2 [IF 2- comm; PRESSES This invention relates to coining presses.

In known coining presses, blanks to be stamped are delivered one at a time between a pair of vertically aligned opposing dies by a carrier member so that each blank lies flat on the face of the lower die within a stationary collar plate through which both dies can move. The upper die then descends to stamp the blank and rises away from it to allow the lower die to lift it out of the cover plate and position it for removal by the carrier member. During this working cycle the upper die moves substantially continuously and rises a substantial distance away from the lower die to allow sufficient time for the carrier member to operate before it subsequently descends to perform another stamping operation.

A problem which occurs with such presses is that during the stamping operation the blank expands radially and its edges are forced into tight engagement with the collar plate so that the lower die has subsequently to exert a pressure on the blank to remove it from the collar plate and this pressure may cause the blank to shoot upwards freely when it will not be positioned correctly for removal by the carrier member. This is particularly prone to occur in high speed coining presses which operate at speeds of the order of 350 strokes per minute.

The object of the present invention is to overcome this problem by controlling movement of the ejected blank.

This object is satisfied according to the present invention by arranging that the upper die is mounted on a tooling slide which can slide axially towards and away from the lower die and which is urged resiliently upwards against a stationary stop defining a normal rest position for the upper die just clear of the lower die and free of the carrier member, and by providing actuating means separate from the tooling slide which moves through successive working cycles and which engages and causes movement of the said tooling slide during only a portion of each working cycle, the upper die remaining in said rest position for the rest of the working cycle during which the lower die and carrier member operate to remove a stamped blank. In this way the invention allows the upper die to be maintained close the the stamped blank to prevent it from shooting upwards without reducing the time interval in which the carrier member has to operate.

The actuating means may comprise a press slide which reciprocates along a straight line towards and away from the lower die and which has a tubular portion at its lower end which receives the tooling slide as a slide fit. Because the press slide surrounds the tooling slide it guides it as well as actuating it, and produces a compact structure.

The stationary stop is preferably adjustable along the line of reciprocation of the tooling slide so as to allow adjustment of the normal rest position of the tooling slide, and is further made adjutable to allow the tooling slide to move upwards and give a clearance for die changing. Preferably, the stroke of the tooling slide is 7 FIG. 1 shows a side elevational view through a press slide assembly according to the invention; and

FIG. 2 shows a cross-section along the line 2-2 of FIG. 1.

The press slide assembly comprises a press slide member 1 which is reciprocated along a vertical axis within a stationary guide frame 2 by a conventional toggle mechanism 3. The lower free end of the press slide member 1 is ofa tubular form to receive a tooling slide member 4 as a slide fit along the vertical axis of reciprocation of the press slide member 1. The lower end of the tooling slide member 4 extends from the tubular end of the press slide member 1 and is adapted to be connected to a die carrying assembly 5 which will be described in more detail below. A horizontal stop bar 6 passes through vertical slots 7 and 8 in the press slide and tooling slide members and is mounted at both ends in supports 9 in the guide frame 2. The tooling slide member 4 is urged upwards to engage the stop bar 6 by two compression coil springs 10 which are housed in vertical bores 11 in the lower end of the press slide member 1. Each spring 10 is seated at its lower end on a nut 15 which is fixed in the lower end of the bore 11, and acts upwards against a nut 14 which is mounted at the upper end of a bolt 12 which passes freely through the spring 10 and nut 15 and which is connected at its lower end to an angular flange 13 at the lower end of the tooling slide 4. Each coil spring 10, therefore, acts on its respective nut 14 to urge its respective bolt 12, and thus the tooling slide 4, upwards so that the latter is urged towards the stop bar 6.

When the press is in operation the press slide member 1 is reciprocated continuously by the toggle mechanism 3. During the greater part of each cycle of the press slide member 1, the tooling slide member 4 remains stationary in its rest position in which it is urged upwards into contact with the stop bar 6 by the springs 10. The press slide member is then moving through the upper part of its stroke. However, during the lower part of the stroke of the press slide member 1 the press slide member engages the tooling slide member and the two move together, the tooling slide moving downwards until the press slide member reaches the bottom of its stroke and then returning with the press slide member to its rest position again, by the action of the coil springs 10. The coil springs 10 are continuously compressed and relaxed by movement of the press slide member and also serve to limit rebound of the tooling slide member when it engages the stop bar 6. The engagement between the two slide members 1 and 4 which causes them to move together is effected through a plate 16 between the upper end of the tooling slide member and the pressure slide member. This plate is connected to the press slide member and is interchangeable with plates of different thicknesses so as to allow the lowest position of the tooling slide member to be adjusted.

The supports 9 for the stop bar 6 are connected to the press frame 2 by screws 17 and are each mounted in a vertical slot 18 in the press frame so that a removable portion 19 of the support engages against the upper end of the slot 18. The thickness of the portion 19 therefore determines the vertical position of the supports 9 and allows the vertical position of the stop bar 6 and thus the rest position of the tooling slide member 4 to be preset. The ends of the stop bar 6 within the supports 9 are eccentric with respect to the intermediate length of the stop bar 6 so that the stop bar can be moved vertically by rotating it in the supports 9. Further, the stop bar 6 has two angular positions 180 apart in which it is held in a fixed state by a stop 20 in a support 9 which is spring urged radially into engagement with one or the other of a pair of radially opposed flats 21 at the corresponding end of the stop bar 6. In one angular position, the stop bar is in its lowest vertical position, and in its other angular position it is in its highest vertical position. Normally the stop bar is in its lowest position, the tooling slide then being in its rest position when it en gages the stop bar. At any time, however, the stop bar 6 can be rotated through 180 to bring it to its highest position, this allowing the tooling slide to move vertically from its rest position so that die changing can be carried out.

A die 22 is carried by the die carrying assembly so as to be vertically aligned with and generally disposed above a collar plate 23 and a lower die 24 carried on support means 24. Blanks to be coined are introduced one at a time between the dies by a carrier member 25. This carrier has one or more notches 26 to receive blanks one at a time and to slide each blank over the upper surface of the collar plate so as to be delivered to the central bore of the collar plate 23 and rest on the lower die 24. The lower die 24 and support means 24 remain stationary during the coining operation and the upper die 22 descends to apply pressure to the blank and then returns to its rest position. The support means 24' then moves upwards causing the lower die 24 to eject the blank from the collar plate and position it in the notch 26 of the carrier member 25 so that it can be carried away, over the surface of the collar plate, by the carrier member. The coining pressure exerted by the upper die 22 causes the blank to expand radially slightly within the collar plate 23 so that its edges tightly engage the sides of the bore in the collar plate. The lower die 24 has therefore to apply pressure on the blank to eject it and as a result may cause it to shoot upwards freely. In order that this movement of the blank is controlled so that it is received within and carried away correctly by the carrier member, the upper die has its rest position preset only just above the upper surface of the carrier member 25. The ejected blank is then confined within a volume defined by the two dies 22, 24 and the notch 26 in the carrier member 25. Preferably the distance between the surface of the die 17, when in its rest position, the upper surface ofthe carrier member 31 is 0.01 inches. The upper lip or edge of the collar plate 23 is bevelledto facilitate removal of the coined blank from between the dies 22, 24.

The die carrying assembly 5 which carries the die 22 comprises a holder 30 which is connected to the tooling slide member 4, and a die head 27 which actually carries the die 22. The die head 27 has a short shank of circular outline which is rotatably received in a cor respondingly shaped recess in the lower face of the holder 30, these two members being substantially axially aligned with the axis of reciprocation. A lock plate 28 is connected to the lower face of the holder 30 around the die head 27 to prevent them from coming axially apart. Further two adjusting screws 31 are provided which pass horizontally through the holder 30 to engage notches 32 in the shank of the die head 27. These screws 31 are directed to be substantially parallel to tangents of the shank of the die head 27 so as to act on the die head 27 to rotate it when screwed inwards, each of these screws 31 further being directed to cause rotation in the opposite directionto the other. Clearly one screw 31 has to be screwed out to allow rotation as the other is screwed in. The lock plate 28 as well as holding the holder 30 and die heat 27 together,

also serves to lock the die head in position once adjusted. This is preferably achieved by providing co-acting frusto-conical surfaces 29 on the die head and lock plate, which cause the die-head to be pushed upwards into the recess in the holder as the plate is tightened.

The die 22 is connected to the die head 27 by a nut 33 which passes over the die and is screwed onto the die head, the die being held against the lower surface of the die head by coacting frusto-conical surfaces 34 on the nut and die. Once the die is connected in place its angular position about the axis of reciprocation can then be easily adjusted using the adjusting screws 31 so that it matches up with the lower die 24 and the two sides of the blank are stamped in the correct relative orientations. An angular adjustment of 10 will normally be sufficient in coining presses.

The die carrying assembly 5 is also adapted so as to allow adjustment of the angle of tilt of the axis of the die 22 and die head 27 relative to the axis of reciprocation. This is achieved by making the holder 30 in three generally horizontal sections 30', 30" and 30" which are mounted one on top of the other so as to slide on mating surfaces 35 and 36 between the members 30, 30" and 30" respectively. The surface 35 is spherical to allow the angle of tilt to be adjusted, and the surface 36 is flat to allow the axis of the die head 27 to be translated with respect to the axis of reciprocation. The three sections of the holder 30 are held together by adjustment screws 37 which are threaded in downwardly projecting flanges of the two upper sections 30" and 30" and which are inclined slightly upwards to engage around the sides of the sections 30 and 30 respectively.

I claim:

1. A coining press comprising first and second coining dies which are opposed to one another along a central longitudinal axis; a collar plate which is disposed in a plane perpendicular to said longitudinal axis and which has a bore therethrough which is axially aligned with said longitudinal axis and which is shaped to receive successive blanks for coining; support means on which said first die is mounted and which holds this die stationary within said bore in the collar plate during coining and which subsequently moves this die along said longitudinal axis towards said second die to eject successively coined blanks from said bore; feed means on the opposite side of said collar plate to said support means which moves in a plane perpendicular to said horizontal axis to insert and remove successive blanks from between said dies; a tooling slide on which said second die is mounted and which can reciprocate along said longitudinal axis; a stationary stop which serves to arrest movement of said tooling slide away from said first die and which when in engagement with said tooling slide holds the latter in a position with the second die just free of said feed means; return means which acts to urge said tooling slide resiliently away from said first die towards engagement with said stationary stop; and actuating means separate from said tooling slide which moves through successive working cycles and which engages and causes movement of said tooling slide during only a portion of each cycle, said movement of the tooling slide comprising movement towards and away from said first die to cause coining of a blank between said dies.

2. A press as claimed in claim 1 in which said actuating means comprises a press slide which reciprocates along a straight line towards and away from said first die and which has a tubular end portion nearest said first die which receives said tooling slide as a slide fit along said line of reciprocation of the press slide.

3. A press as claimed in claim 2 in which said sta' tionary stop is a bar which extends through longitudinal slots in said press slide and tooling slide tranversely of said line of reciprocation of the press slide and which is adjustable along said line of reciprocation.

4. A press as claimed in claim 3 in which the ends of said stop bar are mounted eccentrically with respect to the stop bar in fixed mountings and in which said stop bar is rotatable within said mountings between two set angular positions in each of which said stop bar is in a different position along said line of reciprocation of the press slide said stop bar normally being in one position and being moved to the second position to allow said tooling slide to move away from the first die for die changing.

5. A press as claimed in claim 11 in which said return means comprises a plurality of compression coil springs, each of which is housed within said press slide and has one end engaging abutment means fixed to the press slide and the other end engaging means fixed to one end of a longitudinal rod which passes freely through said spring and abutment means and is connected at its other end to said tooling slide.

6. A press as claimed in claim 2 in which means is provided within said tubular end. portion of the press slide between transversely extending surfaces on said press slide and tooling slide through which said press slide transfers thrust to said tooling slide and-which can be preset to determine the longitudinal positions of said press slide and tooling slide relative to one another when they move together. 

1. A coining press comprising first and second coining dies which are opposed to one another along a central longitudinal axis; a collar plate which is disposed in a plane perpendicular to said longitudinal axis and which has a bore therethrough which is axially aligned with said longitudinal axis and which is shaped to receive successive blanks for coining; support means on which said first die is mounted and which holds this die stationary within said bore in the collar plate during coining and which subsequently moves this die along said longitudinal axis towards said second die to eject successively coined blanks from said bore; feed means on the opposite side of said collar plate to said support means which moves in a plane perpendicular to said horizontal axis to insert and remove successive blanks from between said dies; a tooling slide on which said second die is mounted and which can reciprocate along said longitudinal axis; a stationary stop which serves to arrest movement of said tooling slide away from said first die and which when in engagement with said tooling slide holds the latter in a position with the second die just free of said feed means; return means which acts to urge said tooling slide resiliently away from said first die towards engagement with said stationary stop; and actuating means separate from said tooling slide which moves through successive working cycles and which engages and causes movement of said tooling slide during only a portion of each cycle, said movement of the tooling slide comprising movement towards and away from said first die to cause coining of a blank between said dies.
 2. A press as claimed in Claim 1 in which said actuating means comprises a press slide which reciprocates along a straight line towards and away from said first die and which has a tubular end portion nearest said first die which receives said tooling slide as a slide fit along said line of reciprocation of the press slide.
 3. A press as claimed in claim 2 in which said stationary stop is a bar which extends through longitudinal slots in said press slide and tooling slide tranversely of said line of reciprocation of the press slide and which is adjustable along said line of reciprocation.
 4. A press as claimed in claim 3 in which the ends of said stop bar are mounted eccentrically with respect to the stop bar in fixed mountings and in which said stop bar is rotatable within said mountings between two set angular positions in each of which said stop bar is in a different position along said line of reciprocation of the press slide said stop bar normally being in one position and being moved to the second position to allow said tooling slide to move away from the first die for die changing.
 5. A press as claimed in claim 1 in which said return means comprises a plurality of compression coil springs, each of which is housed within said press slide and has one end engaging abutment means fixed to the press slide and the other end engaging means fixed to one end of a longitudinal rod which passes freely through said spring and abutment means and is connected at its other end to said tooling slide.
 6. A press as claimed in claim 2 in which means is provided within said tubular end portion of the press slide between transversely extending surfaces on said press slide and tooling slide through which said press slide transfers thrust to said tooling slide and which can be preset to determine the longitudinal positions of said press slide and tooling slide relative to one another when they move together. 